Current these commands only check if a container exists in libpod. With
this fix, the commands will also check if they are in containers/storage.
This allows users to look at differences within a buildah or CRI-O container.
Currently buildah diff does not exists, so this helps out in that situation
as well as in CRI-O since the cri does not implement a diff command.
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>